US Patent 7901829 Enhanced catalyst interface for membrane electrode assembly

A membrane electrode subassembly includes an ion conducting membrane and a microporous layer having microtextured surfaces. Complementary features of the microtextured surfaces may be formed as grooves, ridges, pyramids or other shapes. Features of the microtextured surface of the ion conducting membrane engage features of the microporous layer. The engagement of the features of the microtextured surfaces may involve an interlocking fit, a tongue and groove fit, or another type of engagement. A thin catalyst layer is disposed between the microtextured surfaces. The microtextured surfaces increase the surface area at the catalyst layer interfaces.